Particle beam system and method for the particle-optical examination of an object

ABSTRACT

A particle beam system includes a particle source to produce a first beam of charged particles. The particle beam system also includes a multiple beam producer to produce a plurality of partial beams from a first incident beam of charged particles. The partial beams are spaced apart spatially in a direction perpendicular to a propagation direction of the partial beams. The plurality of partial beams includes at least a first partial beam and a second partial beam. The particle beam system further includes an objective to focus incident partial beams in a first plane so that a first region, on which the first partial beam is incident in the first plane, is separated from a second region, on which a second partial beam is incident. The particle beam system also a detector system including a plurality of detection regions and a projective system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of, and claims benefit under35 USC 120 to, U.S. application Ser. No. 15/654,014, filed Jul. 19,2017, now U.S. Pat. No. 10,163,603, which is a continuation and claimsbenefit under 35 USC 120 to, international applicationPCT/EP2016/052291, filed Feb. 3, 2016, which claims benefit under 35 USC119 of German Application No. 10 2015 202 172.6, filed Feb. 6, 2015. Theentire disclosure of these applications are incorporated by referenceherein.

FIELD

The disclosure relates to a particle beam system which operates with amultiplicity of particle beams.

BACKGROUND

WO 2005/024881 A2 discloses a multiple particle beam system in the formof an electron microscopy system which operates with a multiplicity ofelectron beams in order to scan an object to be examined in parallel byway of a bundle of electron beams. The bundle of electron beams isproduced by virtue of an electron beam produced by an electron sourcebeing directed to a multi-aperture plate which has a multiplicity ofapertures. Some of the electrons of the electron beam impinge on themulti-aperture plate and are absorbed there, and another part of thebeam passes through the apertures of the multi-aperture plate such thatan electron beam is formed in the beam path behind each aperture, thecross section of which electron beam is defined by the cross section ofthe aperture. Furthermore, suitably selected electric fields, which areprovided in the beam path upstream and/or downstream of themulti-aperture plate, lead to each aperture in the multi-aperture plateacting as a lens on the electron beam passing through the aperture, andso said electron beam is focused in a plane which lies at a distancefrom the multi-aperture plate. The plane, in which the foci of theelection beams are formed, is imaged by subsequent optics onto thesurface of the object to be examined such that the individual electronbeams impinge on the object in focus as primary beams. There, theygenerate backscattered electrons or secondary electrons emanating fromthe object, which are formed to form secondary beams and are directedonto a detector via further optics. On said detector, each one of thesecondary beams impinges on a separate detector element such that theelectron intensities detected therewith provide information about theobject at the location at which the corresponding primary beam isincident on the object. The bundle of primary beams is systematicallyscanned over the surface of the object in order to produce anelectron-microscopic image of the object in the manner conventional forscanning electron microscopy.

SUMMARY

The disclosure seeks to provide a multiple beam particle beam systemand, in particular, to further improve the contrast production in such amultiple beam particle beam system. A further goal lies in specifyingdeveloped methods for particle-optical examination of objects.

In accordance with one embodiment, the particle beam system includes aparticle source, configured to produce a first beam of chargedparticles. Furthermore, the particle beam system includes a multiplebeam producer, configured to produce a plurality of partial beams fromthe first incident beam of charged particles, which partial beams arespaced apart spatially in a direction perpendicular to a propagationdirection of the partial beams. Here, the plurality of partial beamsincludes at least a first partial beam and a second partial beam. Theparticle beam system furthermore includes an objective, configured tofocus incident partial beams in a first plane in such a way that a firstregion, on which the first partial beam is incident in the first plane,is separated from a second region, on which a second partial beam isincident. Furthermore, the particle beam system includes a detectorsystem including a plurality of detection regions and a projectivesystem. The projective system is configured to project interactionproducts, which leave the first plane due to the incident partial beams,onto the detection regions of the detector system. Here, the projectivesystem and the plurality of detection regions are matched to one anotherin such a way that interaction products emanating from the first regionof the first plane are projected onto a first detection region of thedetector system and interaction products emanating from the secondregion of the first plane are projected onto a second detection region.Here, the second detection region differs from the first detectionregion. Furthermore, the detector system includes a filter device forfiltering the interaction products in accordance with their respectivetrajectory.

By way of suitable filtering of interaction products in accordance withthe respective trajectory thereof, it is possible to increase thecontrast in an image which is created by merging the output signals ofthe detector system for the various detection regions to form an overallimage. Here, the filtering should not be restricted to masking orsuppressing interaction products whose trajectories extend in an outerregion far away from the optical axis of the projective system.

The charged particles can be electrons or ions. In particular, theinteraction products can be secondary electrons or backscatteredelectrons. However, the interaction products can also be primaryparticles which experience a movement reversal due to a decelerationpotential between the objective and the object, without a physicalscattering process occurring between the primary particles and theobject.

In one embodiment, the filter device has a plurality of first detectionfields, which are associated with the first detection region.Furthermore, the filter device has a plurality of second detectionfields, which are associated with the second detection region. Here,each first and second detection field is embodied to detect theinteraction products incident on the respective detection field in amanner independent of interaction products incident on other detectionfields. Expressed differently, this detector has a multiplicity ofdetection fields for each detection region, which detection fieldsdetect interaction products independently from one another in each case.Such instruments are known from light microscopy, from the documentsU.S. Pat. No. 8,705,172B2 and DE102010049627 A1, and the yet to bepublished German patent application No. 10 2013 218 795.5.

The particle beam system can furthermore include a controller embodiedto separately readout and process detector signals from the plurality ofdetection fields of an associated detection region. Important additionalinformation can be obtained by evaluating the associated detectorsignals generated from the various detection fields. By way of example,an analysis of the detector signals for each detection field renders itpossible to establish whether the associated primary partial beam isincident on an object surface in focus, i.e. whether the surface of theobject coincides with the first plane at the location of the incidentpartial beam. This information can subsequently be used to actuate anautomated adjustment system, such as an autofocus system, a detectoradjustment system or a filter adjustment system, in order to achieveideal focusing of the partial beams on a surface of the object.Furthermore, additional information about the topography of an examinedobject can be obtained at the location at which the associated partialbeam is incident on the object by comparing the detector signals of thedetection fields belonging to the same detection region. Furthermore,averaging the detector signals belonging to the plurality of detectionregions or to a whole image allows information to be obtained about theinclination of the sample within the region defined by the averageddetection regions on the surface of the object (object region).Moreover, the global geometry of the object within the region on thesurface of the object, which is defined by the evaluated detectorsignals, can be determined by evaluating the detector signals belongingto the plurality of detection regions and this information can be usedfor correcting a focus and/or correcting an astigmatism in the objectregions adjacent to the evaluated object region.

In a further embodiment, the detection system can additionally includean element producing a dispersion. The element producing the dispersionthen leads to the interaction products associated with a detectionregion being split in accordance with their respective kinetic energy.By comparing the detector signals belonging to the detection fields ofthe same detection region, it is possible to deduce the kinetic energyof the interaction products when they emerge from the object. A voltagecontrast can be produced thus. Here, a voltage contrast should also beunderstood to mean that, for secondary electrons which emerge from theobject from object regions with different electric charge, the potentialwith which said secondary electrons emerge from the object differs. Oneexample for this are contact holes in semiconductor structures, whichestablish contacts between different planes of the conductor trackstructures. If there is no connection between two planes in such acontact hole, the irradiation with charged particles, e.g. electrons,leads to charging in the contact hole as the charge cannot dissipate.The inelastically scattered particles (e.g. electrons) or secondaryelectrons then start from a different electric potential than in thecase of a contacted contact hole. As a result of the fact that it ispossible to distinguish these electrons from one another due to theirdifferent kinetic energies, which lead to different trajectories due tothe element producing a dispersion, it is possible to detectnon-contacted contact holes with a significantly higher speed as thesignal-to-noise ratio is greatly increased.

As an alternative to an embodiment with an element producing adispersion, the filter device can also be a dispersion-producing imagingenergy filter. The detected interaction products can be split andselected in accordance with their kinetic energies with the aid of suchan energy filter. This embodiment can also be used to produce a voltagecontrast.

In accordance with a further embodiment, the projective system includesa crossover plane and the filter device is embodied as a stop arrangedin the vicinity of this crossover plane. In particular, the stop canhave a ring-shaped aperture. What can be achieved with the aid of thering-shaped stop is that only those interaction products emerging fromthe examined object are detected which emerge from the object under aspecific virtual start angle range. As a result of the ring-shaped stop,there is a selection according to that vector component of the initialvelocity of the interaction products emerging from the object that isdirected parallel to the object surface. As a result of this, it ispossible to obtain additional information about the topography of theobject surface or the material at the object surface at the location onwhich the associated partial beam is incident. In particular, it ispossible to partially filter via the ring-shaped stop the energydistribution of the interaction products passing through the stop. Sincethe energy distribution of the interaction products, particularly in thecase of secondary electrons as interaction products, depends inter aliaalso on the local surface potential and the number of emitted secondaryelectrons, the atomic mass number of the atoms at the location at whichthe secondary electrons emerge from the object, additional informationcan thus be obtained about the material composition of the object at therespective location on the object surface, to the extent thatassumptions can be made about the sample surface.

In accordance with a further embodiment, the projective system caninclude a plurality of particle beam lenses arranged in series behindone another, which produce at least two crossover planes following oneanother in succession. Then respectively one stop can be arranged ineach one of the at least two crossover planes. By way of example, afirst stop can have a central aperture, through which only interactionproducts, the trajectories of which extend sufficiently close to theoptical axis of the projective system, can pass. Using such a “brightfield stop”, it is possible to prevent crosstalk between the variousdetection regions. Expressed differently, what can be prevented with theaid of the “bright field stop” is that interaction products which emergefrom a first region of the first plane impinge on a detection regionthat is associated with a different region in the first plane. Onceagain, a stop with a ring-shaped aperture can be arranged in the secondcrossover plane. Like in the embodiment already described above, it isthen possible to obtain additional information about the atomic massnumber at the object surface and/or generate additional topographycontrast. This can preferably be carried out with a dark field stop.

By varying the focal distances of the particle beam lenses, it ispossible to vary the filter effect obtained by the stops. Hence thefocal distances of the particle beam lenses can be variable in a furtherembodiment.

The particle beam lenses can be embodied as magnetic lenses or aselectrostatic lenses, or they can be embodied as combination lenses withsuperposed magnetic and electrostatic fields.

In accordance with a further embodiment, the particle beam systemfurthermore includes a beam deflection system that is embodied todeflect the first particle beam and the second particle beamperpendicular to the propagation direction thereof. In this case, thecontroller is furthermore embodied to merge detector signals, belongingto different deflections of the partial beams, of the various detectionregions to form an image. By deflecting the partial beams, a whole firstregion can be scanned by each partial beam and the image informationproduced by scanning by way of the plurality of partial beams can bemerged to form an overall image.

In accordance with a further embodiment, the disclosure relates to amethod for particle-microscopic examination of an object, including thefollowing steps:

-   -   simultaneously irradiating the object in a plurality of mutually        separated field regions with respectively one primary beam of        charged particles,    -   collecting interaction products emerging from the object due to        the incident primary beams,    -   projecting the interaction products onto a plurality of        detection regions of a detector in such a way that the        interaction products emerging from two different field regions        are projected onto different detection regions of the detector,        and    -   filtering the interaction products in a manner dependent on        their respective trajectory.

In particular, the interaction products can be filtered in accordancewith their kinetic energy.

As already described further above, the filtering of the interactionproducts can be implemented in one embodiment with the aid of a detectorwhich includes a plurality of mutually independent detection fieldssensitive to interaction products for each detection region. Here, thesignals of the detection fields belonging to the same detection regioncan be evaluated relative to one another in order, for example, toproduce an image with an improved voltage contrast, an improvedtopography contrast or an improved material contrast. Furthermore, it ispossible to highlight edges with a specific alignment or create a heightprofile of the object surface.

The particle beam system is operated in the so-called reflection mode ina further embodiment for a method for particle-microscopic examinationof an object. In this method, an electrostatic potential is applied tothe object to be examined, which potential substantially corresponds tothe electric potential of the particle beam producer or the particlebeam producers (particle source). As a result of the electrostaticpotential applied to the object, the primary particle beams aredecelerated as in the case of an electrostatic mirror to a kineticenergy of zero prior to reaching the object, but in the direct vicinityof the object surface, and accelerated back in the reverse direction,i.e. in the direction back to the objective. Those particles thatexperienced a movement reversal due to the electrostatic potential ofthe object are collected and the collected charged particles aresubsequently projected onto a plurality of detection regions of adetector in such a way that the charged particles collected from twodifferent field regions in the object plane are projected onto differentdetection regions of the detector. There is filtering of the collectedparticles as a function of their respective trajectory in thisembodiment of a method according to the disclosure as well. Here, thecollected particles can be filtered with the aid of a detector which hasa plurality of mutually independent detection fields sensitive to thecollected particles for each detection region.

When operating the particle beam system in the reflection mode forexamining electrically nonconductive objects, it is possible tovirtually completely avoid local electric charging of the object by theincident primary beams in the case of suitably selected radiationparameters since the primary particles of the partial beams do notpenetrate into the object. If the object potential is varied, it ispossible to determine the object potential at which the primaryparticles land on the object surface with vanishing kinetic energy. As aresult of this, it is possible to determine the electric potential ofthe object charge. If this is carried out for a multiplicity ofdifferent points on the object surface, it is possible to determine theelectric potential profile in the vicinity of the object surface. As aresult of the above-described filtering of the interaction products, itis moreover possible to determine the trajectories of said interactionproducts. The trajectories allow the form of the local potential profilein the vicinity of the surface of the object to be deduced, and fromthis it is possible to deduce the local topography of the objectsurface. As a result of the “contactless” sensing of the surface, it ispossible to largely dispense with methods for charge compensation. Inparticular, it is possible to determine the sample topography with ahigher accuracy from a plurality of data records by varying parameterssuch as object potential or focal position of the multiple beam particlebeam system. Accordingly, the method can also contain the steps ofvarying the object potential, determining the potential profile in thevicinity of the object surface and determining the local topography ofthe object surface from the local potential profile in the vicinity ofthe surface of the object.

In a further embodiment of a method for particle-microscopic examinationof an object using a multiple beam particle beam system, the interactionproducts, which emerge from the object due to the incident primarybeams, are initially collected with a first suction field and projectedonto a plurality of detection regions of a detector in such a way thatthe interaction products emerging from two different field regions areincident on different detection regions of the detector. Subsequently,the interaction products which emerge from the object due to theincident primary beams are collected with the aid of a second suctionfield, which differs from the first suction field. The interactionproducts collected by the second suction field are subsequently also inturn projected onto a plurality of detection regions of a detector insuch a way that the secondary particles emerging from the object fromtwo different field regions are projected onto different detectionregions of the detector. Subsequently, the detector signals belonging todifferent suction fields but the same detection region are combined withone another by calculation in such a way that a data signal enriched bytopography effects of the object is produced, which is then subsequentlyused for image production and image depiction. This method can beperformed analogously for three, four or more different suction fieldsin order to achieve a higher accuracy when combining by calculation. Ifthe suction field is able to penetrate into the object, this method canalso be used to image structures below the object surface, which are notvisible in the individual images.

In the above-described method, in which interaction products aredetected in different suction fields, it is also possible, prior to thedetection of the interaction products, to additionally carry outfiltering of the interaction products in a manner dependent on theirrespective trajectory. As described above, the filtering can beimplemented by Fourier filtering in a crossover plane with a stop with acircular or ring-shaped aperture that is transmissive for interactionproducts. As an alternative thereto and as was likewise alreadydescribed further above, the filtering of the interaction products canbe implemented with the aid of a detector which has a plurality ofmutually independent detection fields sensitive to interaction productsfor each detection region.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, details of the aforementioned and further embodiments areexplained on the basis of the figures.

FIG. 1 shows a schematic diagram of an embodiment of a multiple beamparticle beam instrument.

FIG. 2 shows a schematic diagram of a detector system in firstembodiment.

FIG. 3 shows a top view of a stop with a ring-shaped aperture.

FIG. 4 shows a schematic diagram of a second embodiment of a detectorsystem.

FIG. 5 shows a schematic diagram of a further embodiment of a detectorsystem.

FIG. 6 shows a top view of a stop with a circular aperture.

FIG. 7 shows a schematic diagram of an embodiment of a detector systemwith a detector which has a multiplicity of detection fields for eachdetection region.

FIG. 8 shows a top view of a detector with a multiplicity of detectionregions with intensity distributions, indicated thereon in exemplaryfashion, of the interaction products incident on the detection regions.

FIG. 9 shows a top view of a detector with a multiplicity of detectionregions with intensity distributions, indicated thereon in exemplaryfashion, of the interaction products incident on the detection regions.

FIG. 10 shows a schematic diagram of a detector system with an energyfilter.

FIG. 11 shows a schematic diagram of a detector system with a dispersiveelement.

FIG. 12 shows a top view of a multiple stop with a plurality of brightfield apertures and dark field apertures.

FIG. 13 shows a schematic diagram of a further embodiment of a detectorsystem.

FIG. 14 shows a further top view of a detector with a multiplicity ofdetection regions with intensity distributions, indicated thereon inexemplary fashion, of the interaction products incident on the detectionregions in the case of object charges.

FIG. 15 shows a further top view of the detector from FIG. 14 with amodified assignment between detection fields and detection regions.

FIG. 16 shows a flowchart for a method for amplifying topographyeffects.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a schematic illustration of a particle beam system 1 whichuses a multiplicity of particle beams. The particle beam system 1produces a multiplicity of particle beams which are incident on anobject to be examined in order to generate interaction products, e.g.secondary electrons, there, which interaction products emanate from theobject and are subsequently detected. The particle beam system 1 is ofthe scanning electron microscope (SEM) type, which uses a plurality ofprimary partial beams 3 which impinge at a plurality of locations 5 on asurface of the object 7 and which produce a plurality of spatiallyseparated electron beam spots there. The object 7 to be examined can beof any type and, for example, include a semiconductor wafer, abiological sample and an arrangement of miniaturized elements or thelike. The surface of the object 7 is arranged in a first plane 101(object plane) of an objective lens 102 of an objective lens system 100.

The magnified section I1 in FIG. 1 shows a top view of the object plane101 with a regular rectangular field 103 of impingement locations 5formed in the first plane 101. In FIG. 1, the number of impingementlocations is 25, which form a 5×5 field 103. The number 25 ofimpingement locations is a small number selected in order to simplifythe illustration. In practice, the number of beams or impingementlocations can be selected to be substantially greater, such as e.g.20×30, 100×100 and the like.

In the illustrated embodiment, the field 103 of impingement locations 5is a substantially regular rectangular field with a constant distance P₁between adjacent impingement locations. Exemplary values for thedistance P₁ are 1 micrometer, 10 micrometers and 40 micrometers.However, it is also possible for the field 103 to have differentsymmetries, such as e.g. a hexagonal symmetry.

A diameter of the beam spots formed in the first plane 101 may be small.Exemplary values for this diameter are 1 nanometer, 5 nanometers, 10nanometers, 100 nanometers and 200 nanometers. Focusing of the particlebeams 3 to form the beam spots 5 is implemented by the objective lenssystem 100.

The primary particles impinging on the object produce interactionproducts, for example secondary electrons, backscattered electrons orprimary particles which have experienced a movement reversal for otherreasons, which emanate from the surface of the object 7 or from thefirst plane 101. The interaction products emanating from the surface ofthe object 7 are formed by the objective lens 102 into secondaryparticle beams 9. The particle beam system 1 provides a particle beampath 11 in order to feed the multiplicity of secondary particle beams 9to a detector system 200. The detector system 200 includes particleoptics with a projection lens 205 to direct the secondary particle beams9 onto a particle multi-detector 209.

The section I2 in FIG. 1 shows a top view of a plane 211, in whichindividual detection regions of the particle multi-detector 209, onwhich the secondary particle beams 9 impinge at locations 213, lie. Theimpingement locations 213 lie in a field 217 with a regular distance P₂from one another. Exemplary values of the distance P₂ are 10micrometers, 100 micrometers and 200 micrometers.

The primary particle beams 3 are produced in a beam production apparatus300, which includes at least one particle source 301 (e.g. an electronsource), at least one collimation lens 303, a multi-aperture arrangement305 and a field lens 307. The particle source 301 produces a divergentparticle beam 309, which is collimated, or largely collimated, by thecollimation lens 303 in order to form a beam 311 which illuminates themulti-aperture arrangement 305.

The section I3 in FIG. 1 shows a top view of the multi-aperturearrangement 305. The multi-aperture arrangement 305 includes amulti-aperture plate 313, which has a plurality of openings or apertures315 formed therein. Center points 317 of the apertures 315 are arrangedin a field 319, which corresponds to the field 103 that is formed by thebeam spots 5 in the object plane 101. A spacing P3 of the center points317 of the apertures 315 from one another can have exemplary values of 5micrometers, 100 micrometers and 200 micrometers. The diameters D of theapertures 315 are smaller than the spacing P3 of the center points ofthe apertures. Exemplary values of the diameters D are 0.2×P3, 0.4×P3and 0.8×P3.

Particles of the illuminating particle beam 311 pass through theapertures 315 and form partial beams 3. Particles of the illuminatingbeam 311 which impinge on the plate 313 are captured by the latter anddo not contribute to forming the partial beams 3.

The multi-aperture arrangement 305 focuses each one of the partial beams3 due to an applied electrostatic field in such a way that beam foci 323are formed in a plane 325. By way of example, a diameter of the beamfoci 323 can be e.g. 10 nanometers, 100 nanometers and 1 micrometer.

The field lens 307 and the objective lens 102 provide first imagingparticle optics for imaging the plane 325, in which the beam foci areformed, onto the first plane 101 such that a field 103 of impingementlocations 5 or beam spots is created there. To the extent that a surfaceof the object 7 is arranged in the first plane, the beam spots areaccordingly formed on the object surface.

The objective lens 102 and the projection lens arrangement 205 providesecond imaging particle optics for imaging the first plane 101 on thedetection plane 211. Therefore, the objective lens 102 is a lens whichis part of both the first and the second particle optics, while thefield lens 307 only belongs to the first particle optics and theprojection lens 205 only belongs to the second particle optics.

A beam switch 400 is arranged in the beam path of the first particleoptics between the multi-aperture arrangement 305 and the objective lenssystem 100. The beam switch 400 is also part of the second particleoptics in the beam path between the objective lens system 100 and thedetector system 200.

Further information in respect of such multiple beam particle beamsystems and components used therein, such as particle sources,multi-aperture plates and lenses can be obtained from the internationalpatent applications WO 2005/024881, WO 2007/028595, WO 2007/028596, WO2011/124352 and WO 2007/060017 and the German patent applications withthe application numbers DE 10 2013 016 113.4 and DE 10 2013 014 976.2,the disclosures of which are included in their entirety in the presentapplication by reference.

Furthermore, the detector system 200 has a filter device 208, with theaid of which the interaction products (e.g. electron beams 9) emergingfrom the object 7 or the first plane 101 are filtered in accordance withthe trajectory thereof. Examples for detector devices with differentfilter devices are described in more detail below on the basis of FIGS.2-15.

The multiple beam particle beam system furthermore has a controller 10,which is embodied both for controlling the individual particle-opticalcomponents of the multiple beam particle beam system and for evaluatingand analyzing the detector signals obtained by the multi-detector 209.Furthermore, the controller 10 is embodied to produce images of objectsurfaces on a reproduction device, e.g. a display, proceeding from thedetector signals generated by the multi-detector 209.

The detector system 200 in FIG. 2 has two further particle beam lenses210, 211 in addition to the projection lens 205 and the multi-detector209. The first further particle beam lens 210 forms a crossover in acrossover plane 214. In this crossover plane 214, the trajectories ofthe interaction products which leave the first plane 101 (object plane)in different regions are superposed. The second additional particle beamlens 211 is operated in such a way that the focal plane thereof issubstantially in the crossover plane 214 of the first additionalparticle beam lens 210. The interaction products emerging in the firstplane 101 in various regions then propagate separately from one anotheragain behind the second additional particle beam lens 211 and they areprojected to the various detection regions 215 of the multi-detector 209by the projection lens 205.

A stop 213, with the aid of which the interaction products can befiltered as desired in accordance with their respective trajectory, isarranged in the crossover plane 214 or in the vicinity of the crossoverplane 214, i.e. between the two additional particle beam lenses 210 and211. Two exemplary stops 213 are depicted in FIGS. 3 and 6. The stop 213depicted in FIG. 3 has a central region 220 and a peripheral region 223,which are both non-transmissive to the interaction products. Between thecentral region 220 and the peripheral region 223, the stop 213 has aring-shaped region that is transmissive to interaction products, saidregion consisting of three ring segments 221, 222, 223 in the depictedembodiment. The webs present between the ring-shaped segments 221, 222,223, which separate the ring-shaped segments from one another, merelyserve to connect the central region 220 and the peripheral region 223 toone another. With the aid of such a ring-shaped stop, it is possible tofilter the interaction products in accordance with their start anglewhen emerging from the object 7 or when leaving the first plane 101.Hence, only those interaction products which left the first plane 101 ina specific angular region can pass the stop in one of the three ringsegments 221, 222, 223 transparent to the interaction products. With theaid of such a stop it is possible to increase the topography contrastsince the interaction products (e.g. secondary electrons) predominantlyemerge under a larger angle of inclination relative to the incidentpartial beams at the edges of the object surface 7.

Since the stop 213 is arranged in a crossover plane 214 of the detectorsystem, only a single ring-shaped stop is used for all partial beams ofthe multiple particle beam system. In this way, the interaction productsproduced from the object 7 by all partial beams of the particle beamsystem experience the same filtering.

In the embodiment in FIG. 2, the two further particle beam lenses 210,211 form a projective system together with the stop 213 and theprojection lens 205.

The stop 213 in FIG. 6 merely has a circular aperture 214 that istransmissive to the interaction products. Crosstalk of the detectionsignals between the detection regions of the detector 209 can be avoidedwith the aid of such a “bright field stop” in the crossover plane 214 ofthe detector system 200 in FIG. 2. Crosstalk between the detectionregions 215 can be created when interaction products that emerge from afield region in the first plane 101 impinge on a detection region 215that is not assigned to this field region. With the aid of the brightfield stop 213 in FIG. 6, it is possible to ensure via a suitableselection of the aperture diameter of the circular aperture 214 that allinteraction products which, due to their trajectory, would impinge on adetection region not associated with the corresponding field region arefiltered out and absorbed by the stop 213. The trajectories of thoseinteraction products which have a combination of large start angles andlarge start energy when emerging from the object extend in the outerregion of the crossover plane in terms of the radial direction. Thecrosstalk between adjacent beams can be reduced by a bright field stop.Moreover, the contrasts, such as e.g. edge contrasts, can be influencedby a bright field stop.

In order to be able to produce different filtering, the stops 213 can bearranged in an interchangeable manner in the detector system 200 andprovision can be made for a plurality of stops with different aperturediameters, ring diameters and ring widths. As an alternative to aninterchangeable stop with only one stop aperture, it is also possible touse multiple stops. A top view of a multiple stop 803 with a pluralityof stop apertures 803 a-803 d is depicted in FIG. 12. In the multiplestops depicted in FIG. 12, two stop apertures 803 a, 803 b each havering-shaped apertures transparent to interaction products, wherein boththe inner diameter and the outer diameter of the ring-shaped aperturesare different. Two further stop apertures 803 c, 803 d are circular andhave different aperture diameters. However, other stop arrangements withmore, or fewer, different stop apertures are possible.

FIG. 13 shows an exemplary embodiment with a detector system, the designof which is similar to the design in FIG. 2. The detector system onceagain includes a first additional particle beam lens 210, which producesa crossover in a crossover plane. A second additional particle beam lens211 is once again operated in such a way that the focal plane thereofcoincides with the crossover plane formed by the first further particlebeam lens 210. The interaction products emerging in various regions inthe first plane 101 then propagate separately from one another againbehind the second additional particle beam lens 211 and they areprojected onto the various detection regions 215 of the multi-detector209 by the projection lens 205. In addition to the exemplary embodimentin FIG. 2, a first double deflection system 801, 802 is arranged betweenthe first additional particle beam lens 210 and the crossover plane anda second double deflection system 803, 804 is arranged between thecrossover plane and the second further particle beam lens in theexemplary embodiment of FIG. 13. A multiple stop 803, as is depicted inan exemplary manner in FIG. 12, is arranged in the crossover plane. Withthe aid of the two double deflection systems 801, 802, 803, 804, one ofthe apertures of the multiple stop 803 can be selected in this exemplaryembodiment, wherein only two apertures 803 a, 803 b of the multiple stopare depicted in FIG. 13. Therefore, depending on the excitation thereof,it is possible, with the aid of the double deflection systems, to switchbetween different contrasts with the aid of the multiple stop. The twodouble deflection systems 801, 802, 804, 805 therefore act as apertureselectors.

In the embodiment in FIG. 13, the two further particle beam lenses 210,211 form a projective system together with the stop 213, the doubledeflection systems 801, 802, 803, 804 and the projection lens 205.

In addition to the projection lens 205 and the multi-detector 209, thedetector system 200 in FIG. 4 has six further particle beam lenses 230,231, 232, 233, 235, 236. The two first further particle beam lenses 230,231 form a first crossover in a first crossover plane 238, the twosubsequent further particle beam lenses 232, 233 form a second crossoverin a second crossover plane 239. The two further particle beam lenses235, 236 following the second crossover plane 239 re-collect theparticle beams of the interaction products emerging from the secondcrossover plane 239 in such a way that the interaction products emergingfrom the various field regions in the first plane 101 are againprojected onto various detection regions 215 of the multi-detector 209with the aid of the projection lens 205 on the multi-detector 209.

In this embodiment of the detector system 200, two different stops 237,234 can be used simultaneously in the first and in the second crossoverplane 238 and 239. By way of example, the bright field stop 213 depictedin FIG. 6 can be arranged in the first crossover plane 238 and the stopwith a ring-shaped aperture depicted in FIG. 3 can be arranged in thesecond crossover plane 239. The suppression of crosstalk between thedetection regions 215 and the targeted filtering of the interactionproducts according to the start angle thereof in the first plane 101 iscarried out simultaneously in this embodiment.

Here, attention is drawn to the fact that the two stops 237, 234 canalso be arranged in an interchanged manner such that a stop with aring-shaped aperture is arranged in the first crossover plane 238 and astop with a central aperture is arranged in the second crossover plane239.

By varying the excitations of the further particle beam lenses 230, 231,232, 233, 234, 235, it is possible to set the trajectories of theinteraction products independently of one another in the two crossoverplanes 238, 239. By varying the trajectories in the crossover planes238, 239, it is possible to simulate different stop radii and stopdiameters, without stops needing to be mechanically interchangedherefor. The trajectories when entering into the detector system 200 andwhen entering into the projection lens 205 can be kept constant in thiscase such that the association between the field regions in the firstplane 101 and the detection regions of the multi-detector 209 can bemaintained. The object field transmitted by all partial beams ofinteraction products in the first plane 101 remains unchanged andconstant in the process.

In this case, the further particle beam lenses 230, 231, 232, 233, 235,236 can be either magnetic lenses or electrostatic lenses.

In the embodiment of FIG. 4, the six further particle beam lenses 230,231, 232, 233, 235, 236 form a projective system together with the twostops 234, 237 and the projection lens 205.

The embodiment of the detector system 200 in FIG. 5 has a very similardesign to the detector system 200 in FIG. 4. In particular, the detectorsystem 200 in FIG. 5 once again has a total of six further particle beamlenses 230, 231, 232, 233, 235, 236 in addition to the projection lens205 and the multi-detector 209, of which further particle beam lensesthe first two further particle beam lenses 230, 231 once again produce afirst crossover in a first crossover plane 238 and the two subsequentfurther particle beam lenses 232, 233 once again produce a secondcrossover in a second crossover plane 239. In addition to the embodimentin FIG. 4, the detection system 200 in FIG. 5 has respectively onedeflection system 240, 244 in front of the first crossover plane 238 andbehind the first crossover plane 238 in each case. The detector system200 likewise has respectively one deflection system 241, 242 in front ofand behind the second crossover plane 239. As a result of differentexcitations of the deflection systems in front of and behind therespective crossover plane 238, 239 with respectively one stop 237, 238situated therebetween, it is possible to amplify edge effects in thesignals detected by the multi-detector 209 and it is possible to produceshadow effects. What is important here is that the deflection which thebeams of the interaction products experience by the deflection system244, 241 respectively arranged in front of the crossover plane iscompensated for again by the deflection system 240, 242 arranged behindthe respective crossover plane. Since the crossover plane lies betweenthe two deflection systems respectively assigned to one another, thismeans that the deflection system 244, 241 arranged in front of acrossover plane and the deflection system 240, 242 arranged behind thesame crossover plane can produce identical deflections in the case of aspecific configuration.

It is possible to generate 3D data records of the sample surface byrecording a plurality of images with different deflection angles in thecrossover planes and by evaluating the respectively occurring shadoweffects in a controller 10.

The deflection systems 240, 244, 241, 242 can respectively be embodiedas single deflection systems or as double deflection systems, withsingle deflection systems being sufficient for most applications.

In the embodiment in FIG. 5, the six further particle beam lenses 230,231, 232, 233, 235, 236 form a projective system together with the twostops 237, 238, the deflection systems 240, 244, 241, 241 and theprojection lens 205.

FIG. 7 shows a top view of a multi-detector 209 of a further embodimentof a detection system. This detector 209 also has an associateddetection region 215 a, 215 b, 215 c for each field region in the plane101. However, in this detector 209, each of the detection regions 215 a,215 b, 215 c is once again subdivided into a multiplicity of detectionfields 216 a, 216 b which detect independently of one another. In FIG.7, this subdivision of the detection regions 215 a, 215 b into detectionfields 216 a, 216 b which detect independently of one another is onlydepicted for one column of the detection regions, with the detectionregions 215 b and 215 c. Moreover, respectively 20 detection fields 216a, 216 b are depicted in FIG. 7 for each detection region 215 b, 215 c.However, the number of detection fields 216 a, 216 b per detectionregion 215 b, 215 c can also be a different one; in particular, more, orfewer, detection fields can be present per detection field. The numberof detection fields per detection region preferably lies in the rangebetween 3 and 64. Square or hexagonal arrangements of the detectionfields, but other symmetries as well, are possible. In cases where ahigh measurement speed is not that important, it is also possible forthe number of detection fields per detection region to be significantlylarger.

In this embodiment of the detector system 200, the interaction productsare filtered in accordance with their respective trajectory only whenthe corresponding interaction products impinge on the multi-detector 209by virtue of the output signals of the detection fields 216 a, 216 bbelonging to the same detection region 215 b, 215 c remainingunconsidered for the image production in the subsequent evaluation bythe controller 10, or by virtue of the output signals of the variousdetection fields, which belong to the same detection region, beingcombined with one another in a suitable manner by calculation via thecontroller 10.

A corresponding multi-detector 209 with a multiplicity of detectionfields 216 a, 216 b per detection region 215 a, 215 b, 215 c can beimplemented in many different ways. A first embodiment for such amulti-detector 209 can be a CCD camera with an upstream scintillator.Each pixel of the CCD camera then forms a detection field 216 a, 216 band a plurality of detection fields together then form respectively onedetection region 215 a, 515 b, 215 c. In another embodiment, a fibercable, which transports the light produced in the scintillator by theinteraction products impinging thereon to the detectors, can be arrangedbetween a scintillator and a detector. The fiber cable then has at leastone fiber for each detection field 216 a, 216 b. And the detectorlikewise has a dedicated detector or a dedicated detector pixel for eachdetection field. However, alternatively, a corresponding detector 209can also be a very fast pixelated electron detector, which directlyconverts incident electrons (interaction products, secondary electrons)into an electrical signal. In this case, each detector pixel also formsa detection field. Combinations of the described embodiments are alsopossible. By way of example, fiber cables arranged behind a scintillatorcan lead to a first group of detectors, which have only a singledetector for each detection region. Using a beam splitter arrangedbetween the scintillator and the entry ends of the fiber cable, anotherpart of the light produced in the scintillator can be guided to a secondgroup of detectors which has a plurality of detectors for each detectionregion. Each detector associated with the same detection region thenforms a detection field. Since the two groups of detectors have a verydifferent number of detectors, the two groups of detectors can then beread with correspondingly different clocks for the whole detector group.Since the second group of detectors generally has a lower clock due tothe greater number of detectors, it is possible to obtain signalstherewith which do not require high data rates, such as e.g. signals forcomponents for the beam adjustment, while signals which are used for theimage production are obtained with the first group of detectors.

FIGS. 8 and 9 respectively depict further top views of correspondingmulti-detectors 209, with the intensity distributions of the respectiveparticle beam of the interaction products incident on the respectivedetection region being simultaneously indicated within the detectionregions.

If the objective 102, the beam switch 400 and the projection lens 205were to be absolutely aberration free, and if the object surface wereplane and without charge, the interaction products emerging from eachfield region in the plane 101 would be projected onto the detector 209by the system made of objective, beam switch 400 and projection lens 205in such a way that the intensity distribution in each detection region215 is rotationally symmetric, as is indicated for the intensitydistribution 515 e in a detection region 215 e in FIG. 8. However, dueto various effects, the actual intensity distributions incident on therespective detection region deviate from this ideal case. By way ofexample, such effects can be topography effects of the object surface,which influence the start conditions of the secondary electrons emergingfrom the object, or else sample charge effects. Moreover, intensitydistributions which deviate from the rotational symmetry may occur inthe detection regions due to aberrations in the objective 102, the beamswitch 400 and the projection lens 205. This is indicated in FIG. 9 bythe cross 515 a in the detection region 215 a. If the deviation from therotational symmetry caused by the aberrations is known in the case ofideal focusing, this information can be used to produce an autofocussignal. To this end, the interaction products detected in the individualdetection fields of the same detection region and the detector signalsemerging therefrom can be analyzed in respect of the spatialdistribution thereof. If the established symmetry of the intensitydistribution deviates from the known intended geometry, an adjustment,e.g. refocusing, is involved. Ideal focusing is achieved when thesymmetry of the intensity distribution in a detection region has theintended symmetry. A global displacement or deformation of the intensitydistributions of the interaction products at the detector relative tothe intended positions or intended distributions allows conclusions tobe drawn about the global sample geometry, such as e.g. a sample tilt,or a global sample charge. Here, a sample property is global if itextends over more than one field region of an individual beam.

If a primary partial beam impinges on an edge of the object surface inthe first plane 101, this generally causes both a displacement of theintensity distribution in the plane of the multi-detector 209 and achange in the form of the intensity distribution due to differenttrajectories of the interaction products emerging from the sample. Thisis indicated in FIG. 8 for the intensity distributions 515 c and 515 din the portions 215 c and 215 d. The changed form of the intensitydistribution of the interaction products in the plane of themulti-detector 209 results from a corresponding change in thetrajectories of the interaction products due to the surface topographyor due to other effects, such as e.g. local charging, of the object. Byevaluating the detection signals recorded with the individual detectionfields, it is once again possible to determine both the displacement ofthe intensity distribution of the detected interaction products and thedeviation of the intensity distribution from the rotational symmetry. Byevaluating this additional information, the image informationsubsequently presented to the user can be improved, for example byvirtue of edges being highlighted.

In the reflection mode in particular, it is possible to deduce the localstart angle of secondary electrons by determining the positions thereofon the detector. It is advantageous to let this evaluation be carriedout more than once per image (frame) and it is particularly advantageousto carry this out per scanning pixel. The lateral form of the featurescan be calculated from the start angle distribution together withfurther information about the object, such as material compositionand/or height of the topological features. To this end, the relativepositions of the brightness distributions, as are produced by thesecondary electrons, can be analyzed and the local, relative beam formchanges and beam position changes at the detector can be analyzed.

Charging of the object at the impingement location of a primary particlebeam also leads to a displacement of the intensity distribution of theinteraction products in the detector plane and to a change in the formof the intensity distribution of the interaction products. As depictedin FIG. 14, charging of the object in a charging region 810 can lead tothe interaction products in one part of the detection regions 811 havingbroader intensity distributions. In other detection regions 812, 813,818, the intensity distributions are displaced in relation to the caseof a non-charged object and, in part, also elongated such that ellipticintensity distributions emerge in the plane of the multi-detector 209.In other detection regions 814, 815, the associated locations of whichon the object surface are far enough away from the charging region, thecharging of the object no longer has an effect and the intensitydistributions have their predetermined form and position. There caneasily be crosstalk of the detected signals, particularly in thedetection regions 817, into which the intensity distribution of anadjacent detection region 812 projects.

Charge contrast images can be produced in a targeted manner byevaluating the detector signals in the individual detection fields. Byway of example, this can be brought about by virtue of those points, atwhich a specific form of the intensity distribution of the interactionproducts is detected, being depicted in a special way in the depictedimage. Furthermore, crosstalk can be prevented by virtue of theassociation between the detection regions and the assigned detectionfields being modified on the basis of the intensity distributionsdetermined with the aid of the detection fields. This is depicted inFIG. 15 for three detection regions 811 a, 812 a, 818 a. The detectionfields, which are respectively indicated as a square in FIG. 15, aredetermined proceeding from the respective locally determined intensitydistribution in the individual detection regions, and combined anew toform detection regions 811 a, 812 a, 818 a, in such a way that therespective intensity distribution of the interaction products liescompletely within the boundaries of each detection region. By way ofexample after the reassignment, six detection fields are associated tothe original detection region 811 in FIG. 14, while a detection region812 a with ten detection fields emerges after the reassignment from adifferent original detection region 812. After the reassignment of thedetection fields to the detection regions, the detector signals in alldetection fields are then respectively added to a signal and associatedwith the corresponding object point on the object surface as an imagesignal. Optionally, the reassignment of the detection fields to thedetection regions can be implemented during the evaluation of thedetector signals for individual image points on the object surface.

As described above charging or an excessive edge contrast can lead tocrosstalk (crosstalk between the detector channels) in a multi-detectorwith a single fixed detection region for each image region since thedetected signals, in part, can no longer be uniquely associated with thedetector regions. Using a detector which has a plurality of detectionfields per detection region, that is to say in which a plurality ofdetectors are available for each primary beam, it is possible tore-associate the detection fields associated with each detection regionin such a way, depending on the position of the beams after analysis ofthe beam positions by finding simple contiguous regions with increasedsignal strength, that, firstly, the crosstalk is reduced and, secondly,no detector signal is lost in other channels. It is particularlyadvantageous if this evaluation is implemented not only once per frame,but a number of times per frame or even per pixel. As a result, theconstraints for a possible charge compensation system or topographyconstraints of the object are substantially reduced.

Particularly in the case of charging objects, it is possible by virtueof this method in the reflection mode to deduce the local objectstructure, as described above.

By integrating all detector signals of all detection fields which belongto the same detection region 215 a, it is then also possible to obtainimage information if the irradiation of the object with primary beamsleads to a local sample charging.

The detection system 200 in FIG. 10 has a so-called imaging energyfilter 600, for example an Omega filter, in addition to themulti-detector 209 and the projection lens 205. By way of example, suchan imaging energy filter is described in U.S. Pat. No. 4,740,704 A. Theimaging energy filter 600 images a first input-side plane 601 into anoutput image plane 602 in an achromatic fashion. At the same time, theimaging energy filter images a second input-side plane 603 into a secondoutput-side plane 604, the dispersion plane, in a dispersive fashion. Byarranging a stop in the dispersion plane 604, in which the secondinput-side plane 603 is imaged, it is possible to vary the energy ofthose interaction products that are able to pass the filter 600. Whatcan be achieved in this manner is that only those interaction productswhich emerge from the object with an energy predetermined by the stop inthe dispersion plane 604 are detected by the multi-detector 209. In thisembodiment, the filtering of the interaction products is alsoimplemented in accordance with their respective trajectory in theprojective system, even if the energy filter ensures that the trajectoryof each interaction product depends on the kinetic energy thereof in thefilter. In this embodiment, the imaging energy filter 600 forms theprojective system together with the projection lens 205.

In the manner described above, it is possible to produce voltagecontrast images with the multiple beam system since the energy of theinteraction products is determined by the electric potential of theobject at the location at which the interaction products leave theobject.

FIG. 11 depicts a detector system 200, which has a dispersion-producingelement 700 in addition to the multi-detector 209 and the projectionlens 205. By way of example, such a dispersion-producing element can bea magnetic sector. Interaction products entering thedispersion-producing element 700 are split in the dispersion-producingelement 700 in accordance with the kinetic energy thereof. In this case,the multi-detector 209, like the detector in FIG. 7, has a multiplicityof detection fields 216 a, 216 b for each detection region. Theinteraction products emerging from each field region in the plane 101then impinge on different detection fields 216 a, 216 b of the samedetection region 215 b due to the dispersion in the dispersion-producingelement 700. As a result of a suitable evaluation of the detectorsignals in the various detection fields, it is once again possible toobtain image information which depends on the kinetic energy of theinteraction products which are detected in the respective detectionfield. Since the kinetic energy of the interaction products in turndepends on the electrostatic potential at the location at which theinteraction products left the first plane 101, it is possible to producevoltage contrast images in this manner.

By evaluating the distribution of the signals in the detection fieldsbelonging to the same detection region, it is possible to drawconclusions about the adjustment state of the overall system. Theseconclusions or this information can be used to readjust the system in anautomated manner or to activate automated adjustment actions. Anevaluation of the form of the distribution or an offset of the signalsin the detection fields belonging to the same detection region can alsobe used to draw conclusions about the focusing and other parameters,such as the inclination of the object surface. Additionally oralternatively, the distribution of the signals in the detection fieldsbelonging to the same detection region can be averaged over a pluralityof detection fields and/or over time. This then supplies informationabout global object properties, such as the global inclination of theobject surface relative to the optical axis of the particle beam system.

FIG. 16 describes a method which can be carried out using a particlebeam instrument and by which image information with amplified topographyeffects of the object surface can be obtained. In a first step, theobject surface is simultaneously irradiated in a plurality of mutuallyseparated field regions with a primary beam of charged particles in eachcase. Here, in a step 902, interaction products, which emerge from theobject due to the incident primary beams, are collected with the aid ofa first suction field and the interaction products collected with thefirst suction field are projected onto a plurality of detection regionsof a detector in such a way that the interaction products emerging fromtwo different field regions are projected onto different detectionregions of the detector. Thereafter, the object surface is once againirradiated simultaneously in a further step 903 in the plurality ofmutually separated field regions, respectively with a primary beam ofcharged particles. Here, in a step 904, interaction products whichemerge from the object due to the incident primary beams are collectedwith the aid of a second suction field, wherein the second suction fielddiffers from the first suction field. Here, the interaction productscollected with the second suction field are in turn projected onto theplurality of detection regions of the detector in such a way that theinteraction products emerging from the object from two different fieldregions are projected onto different detection regions of the detector.In a subsequent step 905, the signals detected in the case of the twodifferent suction fields are evaluated together and, in a step 906, adata signal is obtained from the detector signals obtained in the caseof the different suction fields, in which data signal topography effectsof the object are highlighted. The two suction fields in steps 901 and903 should differ significantly from one another in this case; inparticular, the electric field strength of the stronger suction fieldshould be at least 10%, even better more than 20%, greater than theelectric field strength of the weaker suction field at the surface ofthe object. At the same time, the electric field strength of thestronger suction field should be at least 100 V/mm greater than theelectric field strength of the weaker suction field.

What is claimed is:
 1. A particle beam system, comprising: a particlesource configured to produce a first beam of charged particles; amultiple beam producer configured to produce a plurality of partialbeams from a first incident beam of charged particles, which partialbeams are spaced apart spatially in a direction perpendicular to apropagation direction of the partial beams, the plurality of partialbeams comprising at least a first partial beam and a second partialbeam; an objective configured to focus incident partial beams in a firstplane so that a first region, on which the first partial beam isincident in the first plane, is separated from a second region, on whichthe second partial beam is incident; and a detector system, comprising:a projective system; and a plurality of detection regions, wherein: theprojective system is configured to project interaction products, whichleave the first plane due to the incident partial beams, onto theplurality of detection regions; the projective system and the pluralityof detection regions are matched to one another in such a way thatinteraction products emanating from the first region of the first planeare projected onto a first detection region of the detector system andinteraction products emanating from the second region of the first planeare projected onto a second detection region at least partly differentfrom the first detection region; the plurality of detection regions areconfigured so that a plurality of first detection fields are associatedwith the first detection region and a plurality of second detectionfields are associated with the second detection region; for each firstdetection field, the first detection field is configured to detect theinteraction products incident on the respective first detection field ina manner independent of interaction products incident on other detectionfields; for each second detection field, the second detection field isconfigured to detect the interaction products incident on the respectivesecond detection field in a manner independent of interaction productsincident on other detection fields; the particle beam system furthercomprises a controller embodied to separately readout and processdetector signals from the plurality of first and second detection fieldsof an associated detection region; the controller is configured toanalyze detector signals from the plurality of detection fields of anassociated detection region; and the controller is further configured toat least one of determine sample charge effects based on the results ofthe analyzing of the detector signals, to determine, based on theanalyzing of the detector signals, a displacement of an intensitydistribution of the interaction products from intended positions, todetermine, based on the analyzing of the detector signals, a deviationof an intensity distribution of the interaction products from anintended distribution of the interaction products, and to determine,based on the analyzing of the detector signals, an readjustment signalfor the charged particle beam system.
 2. The particle beam system ofclaim 1, wherein the controller is configured to generate a voltagecontrast image on a display based on the results of the analyzing of thedetector signals.
 3. The charged particle beam system of claim 1,wherein the controller is configured to determine, based on theanalyzing of the detector signals, a deviation of an intensitydistribution of the detected interaction products from a rotationalsymmetry.
 4. The charged particle beam system of claim 1, wherein thecontroller is configured to determine a tilt of a sample surfacerelative to the first plane based on the displacement of the intensitydistribution of the interaction products from intended positions.
 5. Thecharged particle beam system of claim 1, wherein the controller isconfigured to determine a tilt of a sample surface relative to the firstplane based on the deviation of the intensity distribution of theinteraction products from the intended intensity distribution.
 6. Thecharged particle beam system of claim 1, wherein the controller isconfigured to determine information about the sample topography based onthe analyzing of the detector signals.
 7. The charged particle beamsystem of claim 4, wherein the tilt of the sample surface is determinedbased on displacements of the intensity distributions in the detectionfields over more than one detection region.
 8. The charged particle beamsystem of claim 7, wherein the controller is configured to average thedisplacements of the intensity distributions over a plurality ofdetection regions to determine the tilt of the sample surface.
 9. Thecharged particle beam system of claim 1, wherein the controller isconfigured to determine a deviation of the intensity distribution of theinteraction products from an intended distribution of the interactionproducts, and to determine a readjustment signal based on the deviationof the intensity distribution from the intended distribution of theinteraction products.
 10. The charged particle beam system of claim 9,wherein the readjustment signal is determined based on the deviation ofthe intensity distribution extending over more than one detection fieldfrom a rotational symmetry.
 11. The charged particle beam system ofclaim 9, wherein the controller is configured to activate automatedadjustment actions based on the readjustment signal.
 12. The chargedparticle beam system of claim 10, wherein the controller is configuredto activate automated adjustment actions based on the readjustmentsignal.
 13. The charged particle beam system of claim 9, wherein theautomated adjustment actions include an adjustment of the projectivesystem.
 14. The charged particle beam system of claim 9, wherein theautomated adjustment actions include a refocusing.
 15. The chargedparticle beam system of claim 9, wherein the automated adjustmentactions include a correction of an astigmatism of the incident partialbeams in the first plane.
 16. A method, comprising: simultaneouslyirradiating an object in a plurality of mutually separated field regionswith respectively one primary beam of charged particles; collectinginteraction products emerging from the object due to the incidentprimary beams; projecting the interaction products onto a plurality ofdetection regions of a detector in such a way that the interactionproducts emerging from two different field regions are projected onto atleast partly different detection regions of the detector; detecting theinteraction products in a manner dependent on their respectivetrajectory, wherein the interaction products are detected via a detectorwhich comprises a plurality of mutually independent detection fieldssensitive to interaction products for each detection region, thedetecting providing a recorded detector signal for each detection field;and evaluating an intensity distribution of the detected interactionproducts based on detector signals recorded with the detection fields,wherein the method further comprises at least one of determining samplecharge effects based on evaluating the intensity distribution,determining a displacement of the intensity distribution of theinteraction products from intended positions, determining a deviation ofan intensity distribution of the detected interaction products from anfrom an intended distribution of the interaction, and determining areadjustment signal for the charged particle beam system.
 17. The methodof claim 16, the method further comprising generating a voltage contrastimage on a display based on the results of evaluating the detectorsignals.
 18. The method of claim 16, the method further comprisingdetermining a tilt of a sample surface relative to the first plane basedon the displacement of the intensity distribution of the interactionproducts from intended positions.
 19. The method of claim 16, the methodfurther comprising determining a tilt of a sample surface relative tothe first plane based on the deviation of the intensity distribution ofthe interaction products from the intended intensity distribution. 20.The method of claim 18, the method further comprising determining thetilt of the sample surface based on displacements of the intensitydistribution extending over more than one detection field.
 21. Themethod of claim 20, the method further comprising averaging thedisplacements of the intensity distributions over a plurality ofdetection regions to determine the tilt of the sample surface.
 22. Themethod of claim 16, the method further comprising determining thereadjustment signal based on the deviation of the intensity distributionfrom a rotational symmetry.
 23. The method of claim 15, the methodfurther comprising determining the readjustment signal based on thedeviation of the intensity distribution from the intended intensitydistribution.
 24. The method of claim 22, the method further comprisingdetermining the readjustment signal based on the deviation of theintensity distribution extending over more than one detection field froma rotational symmetry.
 25. The method of claim 16, the method furthercomprising activating automated adjustment actions based on thereadjustment signal.
 26. The method of claim 25, wherein the automatedadjustment actions include a refocusing action.
 27. The method of claim25, wherein the automated adjustment actions include an adjustment ofthe projective system.
 28. The method of claim 25, wherein the automatedadjustment actions include a correction of an astigmatism of theincident partial beams in the first plane.